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Sunday, September 27, 2015

The RMS (Root Mean Square) value is 70.7% of the peak voltage and represents
the amount of power that an AC wave can produce as compared to the equivalent
DC voltage.

The international convention for specifying AC voltage is to
express the RMS value of the wave unless it is otherwise defined. If you read
voltage value as 100VAC, it means 100VAC (RMS). If you want to have peak value
than it would be 141.14VAC peak.

If we apply a 110VAC(RMS) sine wave to a load then it will
produce the same amount of power that a 110VDC steady voltage will produce. It
shall be noted that the actual peak value is 155.5VAC. The alternating nature
of sine wave produces less power than the direct current.

Saturday, September 26, 2015

Displacement
is a vector quantity as it is associated with direction,but distance is
a scalar quantity which does not give any information about direction
of motion.Distance and displacement magnitude are numerically equal only
when the body travels in a straight line from A to B(i.e the shortest
distance from a point to another). Also distance has always a non-zero
magnitude,but displacement can be zero if the body returns to the point
of origin at the end of motion.

The Coke is pumped with CO2 gas for
carbonation process. Coke sealed under pressure condition. Partial gas gets
dissolved in the liquid as bubbles and the remaining occupy the volume at the surface
of the liquid and sealed cap. When the bottle is opened due to pressure
difference, there is rush of gas at liquid surface to outside the bottle followed
by dissolved gas rushing out from liquid making small explosions of liquid at
surface leading to hissing sound and bubbles.

Radioactive C-14 is produced in our atmosphere by the bombardment of N-14 by neutrons produced by cosmic rays. The radioactive carbon-14 combines with oxygen to form carbon dioxide and is incorporated into the cycle of living things.

Carbon-14 decays with a half life of about 5730 years by the emission of an electron of energy 0.016 MeV. This changes the atomic number of the nucleus to 7, producing a nucleus of nitrogen-14. At equilibrium with the atmosphere, a gram of carbon shows an activity of about 15 decays per minute.

Presuming the rate of production of
carbon-14 to be constant, the activity of a sample can be directly compared to
the equilibrium activity of living matter and the age calculated.

When living organisms die, their
intake of 14C ceases, and the ratio of 14C / 12Cdecreases as 14C decays. The
period just before 9000 years ago had a higher 14C / 12C
ratio by factor of about 1.5 than it does today.

Because the half-life of 14C
is 5730 years, it is convenient to use the 14C / 12C
ratio to determine the age of objects over a range up to 45,000 years ago.